205 research outputs found
Unraveling the MNE wage premium
Whereas IB has extensively studied MNEs’ generic (positive) impact on host economies, but rarely on employee wages, economics research has only shown an overall MNE wage premium. We ‘unravel’ this premium, considering multiple levels of analysis and accounting for host-country contextual contingencies, to unveil MNEs different (positive or negative) distributional effects. Using unique micro-level data from over 40,000 employees in 13 countries, we examine MNEs’ distributional effects for employees’ gender, experience, and immigrant status; the influence of host-country property rights protection and labor regulation; and interplays with region and industry effects. MNEs’ distributional effects show marked differences that largely depend on the host-country context, and that are positive for experienced and foreign-born employees in developed countries but negative for females working in developing countries. Whereas in developed countries the gender wage gap is smaller in MNEs than in domestic firms as hypothesized, we find evidence of a larger wage gap in developing countries. The analysis also reveals that the higher host-countries’ level of property rights protection, the lower the MNE wage premium. Our study points at the need to reassess statements about the generic positive impact of MNEs in host countries, particularly in developing countries, and discusses (further) research implications
The atoll source states of 4U 1608-52
We have studied the atoll source 4U 1608-52 using a large data set obtained
with the Rossi X-ray Timing Explorer. We find that the timing properties of 4U
1608-52 are almost exactly identical to those of the atoll sources 4U 0614+09
and 4U 1728-34 despite the fact that contrary to these sources 4U 1608-52 is a
transient covering two orders of magnitude in luminosity. The frequencies of
the variability components of these three sources follow a universal scheme
when plotted versus the frequency of the upper kilohertz QPO, suggesting a very
similar accretion flow configuration. If we plot the Z sources on this scheme
only the lower kilohertz QPO and HBO follow identical relations. Using the
mutual relations between the frequencies of the variability components we
tested several models; the transition layer model, the sonic point beat
frequency model, and the relativistic precession model. None of these models
described the data satisfactory. Recently, it has been suggested that the atoll
sources (among them 4U 1608-52) trace out similar three-branch patterns as the
Z sources in the color-color diagram. We have studied the relation between the
power spectral properties and the position of 4U 1608-52 in the color-color
diagram and conclude that the timing behavior is not consistent with the idea
that 4U 1608-52 traces out a three-branched Z shape in the color-color diagram
along which the timing properties vary gradually, as Z sources do.Comment: 43 pages, 16 figures, ApJ accepte
kHz Quasi-Periodic Oscillations in the low-mass X-ray binary 4U 0614+09
We report on a comprehensive analysis of the kilohertz (above 300 Hz)
quasi-periodic oscillations (kHz QPOs) detected from the neutron star low-mass
X-ray binary 4U0614+09 with the Rossi X-ray Timing Explorer (RXTE). With a much
larger data set than previously analyzed (all archival data from February 1996
up to October 2007), we first investigate the reality of the 1330 Hz QPO
reported by van Straaten et al. (2000). This QPO would be of particular
interest since it has the highest frequency reported for any source. A thorough
analysis of the same observation fails to confirm the detection. On the other
hand, over our extended data set, the highest QPO frequency we measure for the
upper kHz QPO is at about 1224 Hz; a value which is fully consistent with the
maximum values observed in similar systems. Second, we demonstrate that the
frequency dependence of the quality factor and amplitude of the lower and upper
kHz QPOs follow the systematic trends seen in similar systems (Barret et al.,
2006). In particular, 4U0614+09 shows a drop of the quality factor of the lower
kHz QPO above 700 Hz. If this is due to an approach to the innermost stable
circular orbit, it implies a neutron star mass of about 1.9 solar masses.
Finally, when analyzing the data over fixed durations, we have found a gap in
the frequency distribution of the upper QPO, associated with a local minimum of
its amplitude. A similar gap is not present in the distribution of the lower
QPO frequencies, suggesting some cautions when interpreting frequency ratio
distributions, based on the occurrence of the lower QPO only.Comment: 10 pages, 6 color figures, 2 tables, Accepted for publication in
MNRA
XTE J1701-462 and its Implications for the Nature of Subclasses in Low-Magnetic-Field Neutron Star Low-Mass X-Ray Binaries
We report on an analysis of RXTE data of the transient neutron star low-mass
X-ray binary (NS-LMXB) XTE J1701-462, obtained during its 2006-2007 outburst.
The X-ray properties of the source changed between those of various types of
NS-LMXB subclasses. At high luminosities the source switched between two types
of Z source behavior and at low luminosities we observed a transition from Z
source to atoll source behavior. These transitions between subclasses primarily
manifest themselves as changes in the shapes of the tracks in X-ray color-color
and hardness-intensity diagrams, but they are accompanied by changes in the kHz
quasi-periodic oscillations, broad-band variability, burst behavior, and/or
X-ray spectra. We find that the low-energy X-ray flux is a good parameter to
track the gradual evolution of the tracks in color-color and hardness-intensity
diagrams, allowing us to resolve the evolution of the source in greater detail
than before and relate the observed properties to other NS-LMXBs. We further
find that during the transition from Z to atoll, characteristic behavior known
as the atoll upper banana can equivalently be described as the final stage of a
weakening Z source flaring branch, thereby blurring the line between the two
subclasses. Our findings strongly suggest that the wide variety in behavior
observed in NS-LXMBs with different luminosities can be linked through changes
in a single variable parameter, namely the mass accretion rate, without the
need for additional differences in the neutron star parameters or viewing
angle. We briefly discuss the implications of our findings for the spectral
changes observed in NS LMXBs and suggest that, contrary to what is often
assumed, the position along the color-color tracks of Z sources is not
determined by the instantaneous mass accretion rate.Comment: Submitted to ApJ, comments are welcome. 13 pages, 8 figure
Genetic risk factors for clozapine-induced neutropenia and agranulocytosis in a Dutch psychiatric population
Personalised Therapeutic
Relations Between Timing Features and Colors in the X-Ray Binary 4U 0614+09
We study the correlations between timing and X-ray spectral properties in the
low mass X-ray binary 4U 0614+09 using a large (265-ks) data set obtained with
the Rossi X-ray Timing Explorer. We find strong quasi-periodic oscillations
(QPOs) of the X-ray flux, like the kilohertz QPOs in many other X-ray binaries
with accreting neutron stars, with frequencies ranging from 1329 Hz down to 418
Hz and, perhaps, as low as 153 Hz. We report the highest frequency QPO yet from
any low mass X-ray binary at 1329+-4 Hz, which has implications for neutron
star structure. This QPO has a 3.5-sigma single-trial significance, for an
estimated 40 trials the significance is 2.4-sigma. Besides the kilohertz QPOs,
the Fourier power spectra show four additional components: high frequency noise
(HFN), described by a broken power-law with a break frequency between 0.7 and
45 Hz, very low frequency noise (VLFN), which is fitted as a power-law below 1
Hz, and two broad Lorentzians with centroid frequencies varying from 6 to 38 Hz
and 97 to 158 Hz, respectively. We find strong correlations between the
frequencies of the kilohertz QPOs, the frequency of the 6 to 38 Hz broad
Lorentzian, the break frequency of the HFN, the strength of both the HFN and
the VLFN and the position of the source in the hard X-ray color vs. intensity
diagram. The frequency of the 97 to 158 Hz Lorentzian does not correlate with
these parameters. We also find that the relation between power density and
break frequency of the HFN is similar to that established for black hole
candidates in the low state. We suggest that the changing mass accretion rate
is responsible for the correlated changes in all these parameters.Comment: ApJ, referee
The biomechanical fingerprint of hip and knee osteoarthritis patients during activities of daily living
Background: Osteoarthritis is a highly prevalent disease affecting the hip and knee joint and is characterized by load-mediated pain and decreased quality of life. Dependent on involved joint, patients present antalgic movement compensations, aiming to decrease loading on the involved joint. However, the associated alterations in mechanical loading of the ipsi- and contra-lateral lower limb joints, are less documented. Here, we documented the biomechanical fingerprint of end-stage hip and knee osteoarthritis patients in terms of ipsilateral and contralateral hip and knee loading during walking and stair ambulation. Methods: Three-dimensional motion-analysis was performed in 20 hip, 18 knee osteoarthritis patients and 12 controls during level walking and stair ambulation. Joint contact forces were calculated using a standard musculoskeletal modelling workflow in Opensim. Involved and contralateral hip and knee joint loading was compared against healthy controls using independent t-tests (p < 0.05). Findings: Both hip and knee cohorts significantly decreased loading of the involved joint during gait and stair ambulation. Hip osteoarthritis patients presented no signs of ipsilateral knee nor contralateral leg overloading, during walking and stair ascending. However, knee osteoarthritis patients significantly increased loading at the ipsilateral hip, and contralateral hip and knee joints during stair ambulation compared to controls. Interpretation: The biomechanical fingerprint in knee and hip osteoarthritis patients confirmed antalgic movement strategies to unload the involved leg during gait. Only during stair ambulation in knee osteoarthritis patients, movement adaptations were confirmed that induced unbalanced intra- and inter-limb loading conditions, which are known risk factors for secondary osteoarthritis.</p
The biomechanical fingerprint of hip and knee osteoarthritis patients during activities of daily living
Background: Osteoarthritis is a highly prevalent disease affecting the hip and knee joint and is characterized by load-mediated pain and decreased quality of life. Dependent on involved joint, patients present antalgic movement compensations, aiming to decrease loading on the involved joint. However, the associated alterations in mechanical loading of the ipsi- and contra-lateral lower limb joints, are less documented. Here, we documented the biomechanical fingerprint of end-stage hip and knee osteoarthritis patients in terms of ipsilateral and contralateral hip and knee loading during walking and stair ambulation. Methods: Three-dimensional motion-analysis was performed in 20 hip, 18 knee osteoarthritis patients and 12 controls during level walking and stair ambulation. Joint contact forces were calculated using a standard musculoskeletal modelling workflow in Opensim. Involved and contralateral hip and knee joint loading was compared against healthy controls using independent t-tests (p < 0.05). Findings: Both hip and knee cohorts significantly decreased loading of the involved joint during gait and stair ambulation. Hip osteoarthritis patients presented no signs of ipsilateral knee nor contralateral leg overloading, during walking and stair ascending. However, knee osteoarthritis patients significantly increased loading at the ipsilateral hip, and contralateral hip and knee joints during stair ambulation compared to controls. Interpretation: The biomechanical fingerprint in knee and hip osteoarthritis patients confirmed antalgic movement strategies to unload the involved leg during gait. Only during stair ambulation in knee osteoarthritis patients, movement adaptations were confirmed that induced unbalanced intra- and inter-limb loading conditions, which are known risk factors for secondary osteoarthritis.</p
Millisecond Oscillations in X-Ray Binaries
The first millisecond X-ray variability phenomena from accreting compact
objects have recently been discovered with the Rossi X-ray Timing Explorer.
Three new phenomena are observed from low-mass X-ray binaries containing
low-magnetic-field neutron stars: millisecond pulsations, burst oscillations
and kiloHertz quasi-periodic oscillations. Models for these new phenomena
involve the neutron star spin, and orbital motion closely around the neutron
star and rely explicitly on our understanding of strong gravity and dense
matter. I review the observations of these new neutron-star phenomena and
possibly related ones in black-hole candidates, and describe the attempts to
use them to perform measurements of fundamental physical interest in these
systems.Comment: 40 pages, 17 figures, 4 tables - submitted to the Annual Review of
Astronomy and Astrophysics; to appear September 200
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